如图，⊙O中，AB是直径，半径CO⊥AB，D是CO的中点，DE∥AB，求证：$\stackrel{\wedge }{EC}$=2$\stackrel{\wedge }{EA}$．

    My name is Amy . It is spring now . But my favourite season is summer . I often wear my skirts and T-shirts . Sometimes I wear my jeans . In summer it is often sunny and hot . Sometimes it's rainy in summer . I like swimming , so I usually swim with my friends on weekends in summer . In summer , I like eating ice-creams . They are delicious . I like summer so much . It brings so many wonderful things to me .

81＋81÷9____89

    Mr. Jones had a quarrel with Mrs. Jones the other day. So they were very angry with each other. For several days they did not s____to each other at all. One evening Mr. Jones was very t____ when he came back from work, so he went to bed at once after d____. Of course he did not say a____to Mrs. Jones before he went upstairs. Mrs. Jones washed the dishes and then did some sewing. When she went up to bed much l____ than her husband, she found a p____ of paper on the small table near her bed. On it were the words, 'Mother—Wake me up at 7 a.m.—Father.'

    When Mr. Jones w____ up the next m____, it was nearly 8 a. m. —and on the small table near his bed he saw a____ piece of paper. He took it and r____these words: 'Father—Wake up. It's 7 a.m. —Mother.'

下列关于生物体结构和功能的叙述，正确的是（  ）